The generator matrix

 1  0  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  0  1  1  1  1  X  1  1  1  1  X  1  1  X  1  1  1  1  1  1  1  1
 0  1  1  a a^6*X+a^2 a^3 a^6*X+a^4 a^5 a^6*X+a^6  0 a^6*X+1  a a^6*X+a^2 a^6*X+a^4 a^6*X+a^6 a^3 a^5  1  X a^5*X+a^6 X+a X+a^5  1 a^4*X+1 a^5*X+a^2 a*X+a^3 a^5*X+a^4  X  X a^5*X+1  1 X+a a^5*X+a^4 a^5*X+a^6 a^5*X+a^2 a^4*X+a^3 X+a^5 a*X+a^6 a^3*X+1
 0  0 a^6*X a*X  X  0 a^3*X a^5*X a^4*X a^2*X a*X a^4*X a^3*X  X a^6*X a^5*X a^2*X a*X a^6*X a*X a^5*X  0 a^6*X a^3*X a^4*X  X a^2*X a*X a^5*X a^2*X a^4*X  0 a^4*X  X a^6*X a*X a^4*X a^2*X a^5*X

generates a code of length 39 over F8[X]/(X^2) who´s minimum homogenous weight is 262.

Homogenous weight enumerator: w(x)=1x^0+3920x^262+1680x^263+147x^264+7840x^270+2016x^271+252x^272+13328x^278+3472x^279+77x^280+7x^304+28x^312

The gray image is a linear code over GF(8) with n=312, k=5 and d=262.
This code was found by Heurico 1.16 in 37.1 seconds.